Most sonar systems include a single transducer lying many meters above the seafloor, to produce sonic beams resulting in sonic echoes from objects in the water or on the seafloor. By repeatedly transmitting sonic pulses and detecting the echoes as the sonar system moves, a technician seeks to detect changes indicating the presence of an object. Such systems generally cannot detect small objects lying at or under the seafloor, or provide detailed information as to the characteristics of the object such as its size, its density profile, etc. My earlier U.S. Pat. No. 4,924,449 describes a method for probing the seafloor, which includes a stationary platform and a transducer that can be moved to any one of several different locations on the stationary platform. At each location, the transducer generates a sonic beam and detects the echo from that beam, before being moved to another location. While this approach enables detection of seabed characteristics at several specific locations, it does not enable the rapid generation of a display that enables a person to visualize characteristics of a seafloor area so as to pick out areas of interest or to obtain an understanding of the vitality for flora and fauna, of a seabed area. A system for probing a seabed, which created signals and usually a display, indicating fine details of a seabed, would enable a better assessment of the quality and unique characteristics of a seabed and better detection of areas of interest, which are usually man-made and geological objects of interest, such as breaks in pipelines and cables, buried mines, and buried boulders.